The invention relates to a dry dust filter for application in operations endangered by gas, in particular in underground mining and tunnel construction, the dust filter including a housing, in which one or more dust absorbing filter elements are provided through which filter elements the dust containing air current flows, the filter elements having a dust retaining filter material and/or are suitably designed therefore.
Such dust filters, also known as dry filters, are applied in different industrial fields, in order to settle dusts created in recovery or production processes as early and extensively as possible and therewith to remove such dust out of the airflow. Filter elements are accordingly arranged in a housing mostly made of metal, the filter elements consisting of filter cloth or a suitable knitwear or other similar material, through which the airflow passes so that the alter elements retain the dust during through-flow resulting in purified air flowing out through the outlet side of the housing.
These filter elements are cleaned by beating, counter flow or similar measures, whereby the dropping dust is collected and disposed of. In operations endangered by gas the air current has to be reduced to such an extent that, on impact of corresponding dust particles or other particles taken along by the air current, no sparks are created. Therewith the through-flow of such de-dusters or dust filters is reduced strongly and large plants have to be acquired or other methods for de-dusting have to be searched for.
Especially in operations endangered by gas and thereby in particular in underground mining, also no materials, which impair the remaining plants and in particular the filter self rescue devices, which have to protect workers in these operations, must be released. Such detrimental effects in particular can enter into the environment especially during glowing of parts of the filter elements or when burning, whereas the regulations provide that no toxic or adhesive residue gases are to be released into the environment. The plants, which are installed there, have to be designed correspondingly. In the U.S. Pat. No. 5,868,807 a dust filter with usual filter elements with wire mesh support is described. The crude gas has to pass a layer of fine grain material prior to reaching the filter elements. Nothing is mentioned about application possibilities in operations endangered by gas and the prevention of electrostatic charges. The honeycomb structure of the arrangement according to the U.S. Pat. No. 5,259,190 A is provided for the ignition of gas or the combustion of carbon dust. In the filter for diesel power machines according to WP93/13303 the filter bodies are joined to an energy supply. Nothing is said about preventing electrostatic charges.